716
FXUS63 KBIS 092102
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
402 PM CDT Wed Jul 9 2025

.KEY MESSAGES...

- Hot and humid conditions are expected into this evening.
  Dangerous heat index values expected across south central
  North Dakota through much of the evening.

- Isolated to scattered severe thunderstorms are possible
  through this evening, and again Thursday afternoon into the
  night.

- Temperatures will cool down to the 70s on Friday, before
  warming back up again for the weekend.

&&

.DISCUSSION...
Issued at 400 PM CDT Wed Jul 9 2025

Hot and humid conditions with chances for severe thunderstorms
are expected through this evening. Southerly flow along a warm front
has brought dewpoints into the 70s for much of central and
southern North Dakota. The hottest areas in this moist southerly
flow could see heat index values above 100 degrees through much
of the evening. A Heat Advisory remains and was expanded
slightly eastward through much of this evening. Meanwhile, a
pseudo dry line is currently progressing across western and
portions of central North Dakota. As this boundary meets the
moist unstable air mass, isolated to scattered severe
thunderstorms will be possible tonight. MUCAPE is very high and
up to 6000 J/KG, with surface based CAPE about the same and
becomes uncapped late this afternoon and early this evening.
There is a lack of shear forecast, with effective bulk shear 25
to 30 knots through the evening. The shear vector is angled to
near perpendicular to the mentioned boundary. Thus discrete
cells are possible initially along this boundary this afternoon
and early evening, likely forming into a line as storms progress
through the evening. Initial threats will be large and abundant
hail with the high amounts of CAPE expected. The lack of shear
may limit the size of hail to around golf ball size. As storms
collapse if a linear mode takes over, strong wind gusts in
excess of 70 mph are possible given DCAPE values over 1000 J/KG.
East of Highway 83 would be the area to monitor for a tornado
or two this evening given high amount of SRH and 0 to 1 km wind
shear. Uncertainty on storm mode, if it is still discrete by the
time storms move into this area later this evening, could be
the limiting factor for tornadoes today. Something to monitor
throughout the evening. Slow moving thunderstorms and high pwat
values today could also lead to some locally heavy rainfall
through this evening. Initial thunderstorms push eastward
tonight, although a few isolated thunderstorms are possible in
the west and central through tonight, with a low chance of
severe weather in this additional development. Lows tonight look
to be in the 60s.

True cold front looks to push through on Thursday. This could
bring an isolated threat for severe weather to much of the
state. Instability and shear look to be lower for Thursday, and
SPC now has a Marginal Risk across much of the state for severe
weather. Slower moving thunderstorms and high PWAT values could
bring another locally heavy rain threat on Thursday, with a
marginal risk for excessive rainfall across the east.
Temperatures will again be warm for Thursday, with slightly
cooler temperatures in the northwest. Lower dewpoints should
lower the heat risk for most areas, although could be something
to monitor in the east. Front fully moves through Thursday
evening through the night. Chances for showers and thunderstorms
could be found as this moves through, with perhaps an isolated
strong to severe thunderstorm. Lows behind the front will be in
50s west to 60s east. A post frontal day then looks to be found
on Friday with highs in the 70s and a few lingering showers and
thunderstorms, with low chances for severe weather. Some breezy
northwest winds could also be found. Lows Friday night look to
be quite cool with lows in the 50s to perhaps upper 40s in some
areas. Shower and thunderstorm chances also diminish Friday
night.

Weak ridging then looks in store for the weekend. Temperatures
look to warm each day with 80s to lower 90s forecast. Chances
for precipitation also look limited through the weekend. Precipitation
chances return to start the work week. NSSL machine learning
guidance has some low probabilities for severe weather Monday
and Tuesday. Warm temperatures in the 80s and 90s could
continue for Monday, then perhaps cool into the 70s on Tuesday
behind the front. Perhaps some breezy winds are found behind
this cold front, although the signal for strong winds is
currently not found.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 120 PM CDT Wed Jul 9 2025

Mainly VFR conditions expected through the forecast period, with
some showers and thunderstorms possible this afternoon and
evening. Look for clear to partly cloudy skies today. Chances
for showers and thunderstorms will return this afternoon and
continue through this evening, mainly for southern, central, and
eastern sites. Confidence was only high enough to include PROB30
mention in TAFs at this point. An isolated to scattered severe
storm is possible through this evening. Shower and thunderstorm
activity becomes isolated tonight into Thursday morning, with
confidence not high enough to include precipitation mention.
Overall VFR conditions expected through tonight, with brief MVFR
conditions possible with any thunderstorm activity. Southerly
winds today will eventually become a westerly wind throughout
the forecast period as a front moves across the state from west
to east.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT /8 PM MDT/ this evening for
NDZ019-020-034>036-042-045>048-050-051.

&&

$$

DISCUSSION...Anglin
AVIATION...Anglin